EFFECTIVE AGE:
The age of property that is based on the amount of observed deterioration and obsolescence it has sustained, which may be different from its chronological age. If a building has had better than average maintenance, its effective age may be less that the actual age; if there has been inadequate maintenance, it may be greater. A 40-year old building may have an effective age of 20 years due to rehabilitation or modernization.

ECONOMIC LIFE:
The period over which improvements to real property contribute to property value.

REMAINING ECONOMIC LIFE:
The number of years remaining in the economic life of the structure or structural component, as of the date of the valuation. In part, it is a function of the attitudes and reactions of typical buyers in the market, and in part a function of the market reactions to competitive properties on the market

FUNCTIONAL OBSOLESCENCE:
Impairment of functional capacity or efficiency. Functional obsolescence reflects the loss in value brought about by such factors as defects, deficiencies or superadequacies that affect the property item itself or its relation with other items comprising a larger property. The inability of a structure to perform adequately the function for which it is currently employed.

EXTERNAL OBSOLESCENCE:
That loss in value experienced by a structure as a result of negative environmental forces outside the boundaries of the property. Also known as environmental obsolescence or economic obsolescence.

MARKETABLE TITLE:
A title not subject to reasonable doubt or suspicion of invalidity in the mind of a reasonable, intelligent person; one which a prudent person guided by competent legal advice would be willing to accept and purchase at a market value.

RESTRICTIVE COVENANT:
A private agreement that restricts the use and occupancy of real estate that is part of a conveyance and is binding on all subsequent purchasers.